This invention relates to peeling apparatus and, more particularly, to roller-type shrimp-peeling machinery with self-adjusting lower rollers.
Originally introduced because of the high labor costs of peeling small shrimp by hand, shrimp peeling machines are now widely used in the shrimp processing industry. Roller-type shrimp-peeling machines, in particular, dominate the bulk shrimp peeling industry. U.S. Pat. Nos. 2,778,055, Jan. 22, 1957, and 2,537,355, Jan. 9, 1951, both to Fernand S., James M., and Emile M. Lapeyre, describe the basic structure and principles of operation of roller-type shrimp peelers.
U.S. Pat. No. 2,778,055 shows a peeling machine with a rigid framework supporting the peeling elements. A transverse beam divides the machine into two peeling sections. The upper peeling section extends from a rear wall to the beam; the lower peeling section extends from the beam to the lower front end of the machine. Shell-on shrimp are fed over the rear wall to the upper peeling section. Channels are formed in the upper peeling section by groups, or associations, of five rollers for each channel. The association of rollers includes a power roller forming the base of the channel, two channel-forming rollers flanking and spaced slightly above the power roller, and two small-diameter insert rollers between the power roller and the channel-forming rollers. The power rollers extend the full length of the machine through both the upper and lower peeling sections. The power rollers are supported in the lower peeling section by base idler rollers, or lower rollers. All the rollers incline downwardly from the rear wall to the front end of the machine. The channel-forming rollers and the insert rollers extend only the length of the upper peeling section and are mounted at the rear wall and at the transverse beam. The power rollers and the channel-forming rollers are mounted in fixed locations so that their peripheries are separated a distance slightly less than the diameter of the insert rollers. In this way, the insert rollers, which are not fixedly mounted as are the power and channel-forming rollers, can be forcibly urged by spring pressure into the gaps between the power and channel-forming rollers. The spring pressure provides a tight nip between the insert roller and the power roller. In the lower peeling section, two power rollers and a base idler roller, or lower roller, at a lower elevation form an inverted triangular lower peeling channel. The power rollers rotate the lower roller by frictional contact. The power rollers rotate in alternate directions to force shrimp in the upper peeling section into the nips on one side of the channel and then into the nips on the other side of the channel. The shrimp are unwrapped of their shells in the nips, the shells falling as waste through the gaps between the power roller and the channel-forming rollers. Most of the peeling is effected in the upper peeling section. Shells not removed in the upper peeling section are further subjected to pinching action between the large-diameter power rollers and the base idler roller in each channel of the lower peeling section.
The power rollers, the channel-forming rollers, and the lower rollers are typically constructed of a metal tube or pipe having a rubber coating. With use, the rubber coating on the power, channel-forming, and lower rollers wears off and the inside surfaces of their axles wear and gaps form between the rollers. In the lower section, where there are no insert rollers, the gaps between the power rollers and the lower rollers affect the peeling grips and degrade performance. The rollers have to be readjusted with respect to one another to reduce the gaps. This is typically done by manually raising the upper ends of the lower rollers. These manual readjustments have to be performed quite often, and the fastening hardware sometimes comes loose because of inadequate tightening and the vibration of the peeler.